Heat pump boiler

ABSTRACT

A heat pump boiler is disclosed. The heat pump boiler includes a compressor. The heat pump boiler further includes an exterior heat exchanger that is configured to transfer heat between refrigerant and exterior air. The heat pump boiler further includes an interior heat exchanger that is configured to transfer heat between refrigerant and water. The heat pump boiler further includes a channel change valve that is configured to provide refrigerant compressed by the compressor to the exterior heat exchanger or the interior heat exchanger. The heat pump boiler further includes a first boiler heat exchanger that is configured to heat water that has passed through the interior heat exchanger from heat generated through combustion. The heat pump boiler further includes a second boiler heat exchanger that is configured to transfer heat between refrigerant and gas discharged from the first boiler heat exchanger.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2018-0126196, filed on Oct. 22, 2018, which is incorporated byreference.

FIELD

The present disclosure relates to a boiler including a heat pump.

BACKGROUND

A boiler or a heat pump may be used to heat an interior.

A boiler is a device that heats an interior by heating water usingcombustion heat, which is generated when fuel is burned, and supplyingthe heated water having heat to a heating demander through heating pipesinstalled in the interior, and supplies the heated water as hot waterfor a bathroom, a kitchen, etc.

A heat pump can heat an interior by heating the heating water usingheat, which is generated in the process of phase change of arefrigerant, and supplying the heated water to a heating demander.

SUMMARY

A boiler has an advantage that it is possible to temporarily provide alarge amount of heating heat, but there is a problem that a lot of costis required to use fuel. Further, the heat pump generates heat bycirculating a refrigerant by driving a compressor, so a low cost may berequired in comparison to the boiler, but there is a defect that it isimpossible to provide sufficient heating heat at very low temperature.

Accordingly, a heat pump boiler that separately or simultaneously uses aheat pump and a boiler by complementing the advantages and defects of aboiler and a heat pump is being developed.

In a heat pump boiler, there is a need for a separate defrosting processto remove frost that may be produced in an exterior heat exchanger dueto driving of a heat pump.

However, in the structure described above, a refrigerant discharged froma compressor can be sent to an exterior heat exchanger by adjusting theflow direction of the refrigerant to perform a defrosting process, andin this case, heating water may be cooled through an interior heatexchanger. Accordingly, efficiency of interior heating is may decreaseor the amount of fuel that is supplied to a boiler increases.

A first object of the present disclosure is to provide a heat pumpboiler that does not stop a separate heating operation to performdefrosting operation for an exterior heat exchanger.

A second object of the present disclosure is to provide a heat pumpboiler in which hybrid heating efficiency can be maintained by usingheat that is used in existing boilers without introducing an additionalheat source.

The objects of the present disclosure are not limited to the objectsdescribed above and other objects will be clearly understood by thoseskilled in the art from the following description.

According to an innovative aspect of the subject matter described inthis specification, a heat pump boiler includes a compressor that isconfigured to compress refrigerant; an exterior heat exchanger that isconfigured to transfer heat between refrigerant and exterior air; aninterior heat exchanger that is configured to transfer heat betweenrefrigerant and water; a channel change valve that is configured toprovide refrigerant compressed by the compressor to the exterior heatexchanger or the interior heat exchanger; a first boiler heat exchangerthat is configured to heat water that has passed through the interiorheat exchanger from heat generated through combustion; a second boilerheat exchanger that is configured to transfer heat between refrigerantand gas discharged from the first boiler heat exchanger; and adefrosting valve that is configured to provide refrigerant to theinterior heat exchanger or the second boiler heat exchanger.

This implementation and other implementations may each include one ormore of the following optional features. Based on the exterior heatexchanger operating as a condenser, the defrosting valve providesrefrigerant discharged from the exterior heat exchanger to the secondboiler heat exchanger. Based on the exterior heat exchanger operating asan evaporator, the defrosting valve provides refrigerant discharged fromthe compressor to the interior heat exchanger. The heat pump boilerincludes an outdoor unit that includes the compressor, the exterior heatexchanger, and the channel change valve; an indoor unit that includesthe interior heat exchanger, the first boiler heat exchanger, and thesecond boiler heat exchanger; a first refrigerant pipe that defines achannel for refrigerant that is discharged from the outdoor unit andprovided to the indoor unit; and a second refrigerant pipe that definesa channel for a refrigerant that is discharged from the indoor unit andprovided to the outdoor unit.

The defrost valve provides refrigerant provided from the outdoor unitthrough the first refrigerant pipe to the interior heat exchanger or thesecond boiler heat exchanger. The channel change valve includes a firstchannel change valve that is configured to provide refrigerantdischarged from the compressor to the interior heat exchanger or theexterior heat exchanger; a second channel change valve that isconfigured to provide refrigerant discharged from the exterior heatexchanger to the compressor or the second boiler heat exchanger; and athird channel change valve that is configured to provide refrigerantdischarged from the interior heat exchanger to the exterior heatexchanger or provide refrigerant discharged from the second boiler heatexchanger to the compressor. The defrosting valve is configured toprovide, to the interior heat exchanger, refrigerant that is providedthrough the first channel change valve.

The defrosting valve is configured to provide, to the second boiler heatexchanger, refrigerant that is provided through the second channelchange valve. The first boiler heat exchanger includes a sensible heatexchanger that heats water using heat generated through combustion; anda latent heat exchanger that heats water by absorbing condensationlatent heat of an exhaust gas that has passes through the sensible heatexchanger. The second boiler heat exchanger is located downstreamfurther than the latent heat exchanger in a traveling direction of gasthat is burned in the first boiler heat exchanger. The heat pump boilerincludes an exhauster that extends from the first boiler heat exchangerand that is configured to guide exhaust gas discharged by the firstboiler heat exchanger. The second boiler heat exchanger is located inthe exhauster.

The details of other implementations are included in the followingdetailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an example heat pump boiler.

FIG. 2A illustrates refrigerant flow in an internal configuration of anoutdoor unit in a hybrid heating mode of an example heat pump boiler.

FIG. 2B illustrates refrigerant flow in an internal configuration of anoutdoor unit in a defrosting-heating mode of an example heat pumpboiler.

FIG. 3 illustrates flow of heating water and a refrigerant in the hybridheating mode of an example heat pump boiler.

FIG. 4 illustrates flow of heating water and a refrigerant in thedefrosting-heating mode of an example heat pump boiler.

FIG. 5 is a block diagram of a controller and relevant components of anexample heat pump boiler.

FIG. 6 is a schematic of an example heat pump boiler.

DETAILED DESCRIPTION

FIG. 1 is a schematic configuration of an example heat pump boiler. FIG.2A illustrates refrigerant flow in an internal configuration of anoutdoor unit in a hybrid heating mode of an example heat pump boiler.FIG. 2B illustrates refrigerant flow in an internal configuration of anoutdoor unit in a defrosting-heating mode of an example heat pumpboiler. FIG. 3 illustrates flow of heating water and a refrigerant inthe hybrid heating mode of an example heat pump boiler. FIG. 4illustrates flow of heating water and a refrigerant in thedefrosting-heating mode of an example heat pump boiler.

A heat pump boiler includes: a compressor 10 that compresses arefrigerant; an exterior heat exchanger 12 that allows for heat exchangebetween exterior air and a refrigerant; an interior heat exchanger 22that allows for heat exchange between heating water and a refrigerant;channel change valves 14 a, 14 b, and 14 c that send the refrigerantcompressed by the compressor 10 to the interior heat exchanger 22 or theexterior heat exchanger 12; a first boiler heat exchanger 32 that heatsheating water that has passed through the interior heat exchanger 22,using combustion heat; a second boiler heat exchanger 34 that allowsheat exchange between a refrigerant and gas discharged through the firstboiler heat exchanger 32; and a defrosting valve 24 that sends therefrigerant discharged from the exterior heat exchanger 12 to the secondboiler heat exchanger 34 in a defrosting mode.

A heat pump boiler includes the interior heat exchanger 22 that heatsheating water using heat exchange with a refrigerant, and the firstboiler heat exchanger 32 that heats the heating water using combustionheat. In this configuration, the heating water means water as an exampleof a medium for supplying heat to a target to be heated, and fluid otherthan water may be used. The heating water is a medium that flows throughthe first boiler heat exchanger 32 or the interior heat exchanger 22 andis not discriminated from cold water or hot water.

The heat pump boiler can heat heating water through the interior heatexchanger 22 or can heat heating water through a boiler 3. Further, theheat pump boiler can heat the heating water using both of the interiorheat exchanger 22 and the boiler 3.

The compressor 10 discharges a high-temperature and high-pressurerefrigerant by compressing a refrigerant gas and may use a BLDC motor.

The interior heat exchanger 22 allows for heat exchange between theheating water and the refrigerant compressed and discharged from thecompressor 10. A plate heat exchanger that allows for heat exchangebetween a refrigerant and heating water may be used as the interior heatexchanger 22.

The interior heat exchanger 22 may be used as a condenser that heatsheating water by condensing a compressed liquid-state refrigerant. Theinterior heat exchanger 22 can primarily heat heating water that issupplied from a heating demander in a heating mode in which thecompressor 10 is operated. The interior heat exchanger 22 may not besupplied with a refrigerant in a defrosting mode that removes frost inthe exterior heat exchanger 12. Accordingly, in the defrosting mode,heating water and a refrigerant do not exchange heat in the interiorheat exchanger 22. In the defrosting mode, heating water is not heatedin the interior heat exchanger 22.

The exterior heat exchanger 12 can allow for heat exchange betweenexternal air and a refrigerant. The exterior heat exchanger 12 canfunction as an evaporator in which a refrigerant evaporates by takingheat from external air, in the heating mode that heats heating waterusing the interior heat exchanger 22.

However, when the exterior heat exchanger 12 is used as an evaporator atexterior temperature that is a predetermined temperature or less,frosting in which frost is produced outside the exterior heat exchanger12 may occur. In the defrosting mode, the exterior heat exchanger 12 maybe used as a condenser into which the refrigerant compressed by thecompressor 10 flows. Accordingly, in the defrosting mode, therefrigerant compressed by the compressor 10 condenses, whereby frost canbe removed.

The channel change valves 14 a, 14 b, and 14 c can send the refrigerantdischarged from the compressor 10 to the interior heat exchanger 22 orthe exterior heat exchanger 12. The channel change valves 14 a, 14 b,and 14 c are disposed as several pieces in an outdoor unit 1 to bedescribed below and can adjust the refrigerant that is discharged fromthe compressor 10 and the refrigerant that flows into the refrigerator10.

The channel change valves 14 a, 14 b, and 14 c can change the flowdirection of the refrigerant discharged from the compressor 10. Thechannel change valves 14 a, 14 b, and 14 c can send the refrigerantdischarged from the compressor 10 to the exterior heat exchanger 12 orthe interior heat exchanger 22, depending on operation odes of the heatpump boiler.

The channel change valves 14 a, 14 b, and 14 c may include a firstchannel change valve 14 a that sends the refrigerant discharged from thecompressor 10 to the interior heat exchanger 22 or the exterior heatexchanger 12, a second channel change valve 14 b that sends therefrigerant discharged from the exterior heat exchanger 12 to thecompressor 10 or the second boiler heat exchanger 34, and a thirdchannel change valve 14 c that sends the refrigerant discharged from theinterior heat exchanger 22 to the exterior heat exchanger 12 or sendsthe refrigerant discharged from the second boiler heat exchanger 34 tothe compressor 10.

The first boiler heat exchanger 32 can heat the heating water that issupplied to the heating demander using combustion heat. The combustionheat means heat that is generated by combustion of fuel and the fuelthat is used in the boiler may include fossil fuel such as gas.

The first boiler heat exchanger 32 heats the heating water that flowsinside through the interior heat exchanger 22. The first boiler heatexchanger 32 heats heating water, using combustion heat that isgenerated by hearing fuel that is supplied, and discharges gas used forcombustion.

The first boiler heat exchanger 32 may include a heating water pipeforming a channel through which heating water flows, a combustor thatheats the heating water pipe by burning fuel such as gas, and aexhauster to which the gas burned by the combustor is discharged.

The first boiler heat exchanger 32 may include a sensible heat exchanger32 a that directly heats heating water using combustion heat, and alatent heat exchanger 32 b that heats heating water by absorbing againthe condensation latent heat of an exhaust gas that has passed throughthe sensible heat exchanger 32 a.

The second boiler heat exchanger 34 allows for heat exchange betweenexhaust gas discharged from the first boiler heat exchanger 32 and arefrigerant. That is, the second boiler heat exchanger 34 can functionas an evaporator that evaporates a refrigerant using an exhaust gasdischarged through the first boiler heat exchanger 32.

The second boiler heat exchanger 34 is disposed downstream further thanthe latent heat exchanger 32 b in the traveling direction of gas that isburned. The second boiler heat exchanger 34 may be disposed at a side ofthe first boiler heat exchanger 32 in which the latent heat exchanger 32b is disposed.

The heat pump boiler may include a first expansion valve 50 that expandsa refrigerant discharged from the interior heat exchanger 22 and flowinginto the exterior heat exchanger 12; and a second expansion valve 52that expands a refrigerant discharged from the exterior heat exchanger12 and flowing into the second boiler heat exchanger 34. The firstexpansion valve 50 may be disposed between the interior heat exchanger22 and the exterior heat exchanger 12, and the second expansion valve 52may be disposed between the exterior heat exchanger 12 and the secondboiler heat exchanger 34.

The first expansion valve 50 and the second expansion valve 52 may beadjusted to expand a refrigerator in accordance with the operation modesof the heat pump boiler.

The heat pump boiler 3 may include an indoor unit 2 that heats heatingwater using heat exchange with a refrigerant, and an outdoor unit 1 thatis disposed in an exterior space and in which the exterior heatexchanger 12 allowing for heat exchange between external air and arefrigerant is disposed.

The indoor unit 2 is for discrimination from the outdoor unit and is notnecessarily disposed in the interior. However, the outdoor unit 1 may bedisposed in an interior space in terms of including the exterior heatexchanger 12 that allows for heat exchange with external air.

The exterior heat exchanger 12 is disposed in the indoor unit 2. In theindoor unit 2, other than the interior heat exchanger 22, the componentsof the boiler 3 that heats heating water using combustion heat may bedisposed. That is, the interior heat exchanger 22, the first boiler heatexchanger 32, and second boiler heat exchanger 34 may be disposed in theindoor unit 2. However, the inside of the indoor unit 2 may be dividedinto a space in which the interior heat exchanger 22 is disposed and aspace in which the first boiler heat exchanger 32 and the second boilerheat exchanger 34 are disposed.

The interior heat exchanger 22 that heats heating water usingcondensation heat of a refrigerant and the first boiler heat exchanger32 that heats the heating water using combustion heat are disposed inthe indoor unit 2. The second boiler heat exchanger 34 that evaporates arefrigerant using the exhaust gas discharged from the first boiler heatexchanger 32 may be disposed in the indoor unit 2.

Further, the defrosting valve 24 may be disposed in the indoor unit 2.The defrosting valve 24 can send the refrigerant flowing in the outdoorunit 1 to the interior heat exchanger 22 or the second boiler heatexchanger 34.

The compressor 10, the exterior heat exchanger 12, and the channelchange valves 14 a, 14 b, and 14 c are disposed in the outdoor unit 1.The first channel change valve 14 a that sends the refrigerantdischarged from the compressor 10 to the interior heat exchanger 22 orthe exterior heat exchanger 12, the second channel change valve 14 bthat sends the refrigerant discharged from the exterior heat exchanger12 to the compressor 10 or the second boiler heat exchanger 34, and thethird channel change valve 14 c that sends the refrigerant dischargedfrom the interior heat exchanger 22 to the exterior heat exchanger 12 orsends the refrigerant discharged from the second boiler heat exchanger34 to the compressor 10 may be disposed in the outdoor unit 1.

The heat pump boiler includes refrigerant pipes 44 and 46 for flowbetween the outdoor unit 1 and the indoor unit 2. The refrigerant pipes44 and 46 include a first refrigerant pipe 44 that forms a refrigerantchannel through which a refrigerant discharged from the outdoor unit 1is supplied to the indoor unit 2, and a second refrigerant pipe 46through which a refrigerant discharged from the indoor unit 2 issupplied to the outdoor unit.

The first refrigerant pipe 44 sends the refrigerant discharged from thecompressor 10 through the first channel change valve 14 a to thedefrosting valve 24 or sends the refrigerant discharged from theexterior heat exchanger 12 through the second channel change valve 14 bto the defrosting valve 24.

The second refrigerant pipe 46 sends the refrigerant discharged from theinterior heat exchanger 22 to the third channel change valve 14 c orsends the refrigerant discharged from the second boiler heat exchanger34 to the third channel change valve 14 c.

The first channel change valve 14 a, the second channel change valve 14b, and the third channel change valve 14 c are adjusted in accordancewith the operation modes. The first channel change valve 14 a, thesecond channel change valve 14 b, and the third channel change valve 14c are adjusted such that the refrigerant compressed by the compressor 10flows to the indoor unit 2 in the heating mode that heats heating waterthrough the interior heat exchanger 22. Further, the first channelchange valve 14 a, the second channel change valve 14 b, and the thirdchannel change valve 14 c are adjusted such that the refrigerantcompressed by the compressor 10 flows to indoor unit 2 through theexterior heat exchanger 12 in the defrosting mode that removes frostproduced in the exterior heat exchanger 12.

Referring to FIG. 2A, the first channel change valve 14 a can connectthe compressor 10 and the defrosting valve 24, the second channel changevalve 14 b can connect the exterior heat exchanger 12 and the compressor10, and the third channel change valve 14 c can connect the interiorheat exchanger 22 and the exterior heat exchanger 12 to send therefrigerant discharged from the compressor 10 to the interior heatexchanger 22 in the hybrid heating mode.

Referring to FIG. 2B, the first channel change valve 14 a can connectthe compressor 10 and the exterior heat exchanger 12, the second channelchange valve 14 b can connect the exterior heat exchanger 12 and thedefrosting valve 24, and the third channel change valve 14 c can connectthe second boiler heat exchanger 34 and the compressor 10 to send therefrigerant discharged from the compressor 10 to the exterior heatexchanger 12 in the defrosting-heating mode.

The heat pump boiler can be operated in the hybrid heating mode thatprimarily heats heating water through the interior heat exchanger 22 andsecondarily heats the heating water through the first boiler heatexchanger 32, and the defrosting-heating mode that heats heating waterthrough the first boiler heat exchanger 32 and removes frost produced inthe exterior heat exchanger 12.

In each of the hybrid heating mode and the defrosting-heating mode, thecompressor 10 is driven and heating water is heated in the first boilerheat exchanger 32.

Referring to FIG. 3 , in the hybrid heating mode, the interior heatexchanger 22 functions as a condenser. Accordingly, the refrigerantflowing from the outdoor unit 1 flows to the interior heat exchanger 22,thereby being able to heat heating water.

In the hybrid heating mode, the refrigerant compressed by the compressor10 can be discharged from the outdoor unit 1. In the hybrid heatingmode, the defrosting valve 24 connects the compressor 10 and theinterior heat exchanger 22. In the hybrid heating mode, the defrostingvalve 24 sends the refrigerant flowing inside from the outdoor unit 1 tothe interior heat exchanger 22. The refrigerant that has passed throughthe interior heat exchanger 22 is supplied back to the outdoor unit 1,thereby being able to flow to the exterior heat exchanger 12.

The heating water that is supplied to the heating demander can flow tothe first boiler heat exchanger 32 through the interior heat exchanger22. Accordingly, the heating water primarily heated through the interiorheat exchanger 22 can be secondarily heated through the first boilerheat exchanger and then can be supplied to the heating demander.

Referring to FIG. 4 , in the defrosting-heating mode, the second boilerheat exchanger 34 functions as an evaporator. Accordingly, therefrigerant flowing from the outdoor unit 1 can flow to the secondboiler heat exchanger 34 and evaporate.

In the defrosting-heating mode, the refrigerant condensed through theexterior heat exchanger 12 can be discharged from the outdoor unit 1. Inthe defrosting-heating mode, the defrosting valve 24 connects theexterior heat exchanger 12 and the second boiler heat exchanger 34. Inthe defrosting-heating mode, the defrosting valve 24 sends therefrigerant flowing inside from the outdoor unit 1 to the second boilerheat exchanger 34. The refrigerant that has passed through the secondboiler heat exchanger 34 is supplied to the outdoor unit 1, therebybeing able to flow to the compressor 10.

The heating water that is supplied from the heating demander can beheated through the first boiler heat exchanger and supplied to theheating demander. The heating water that is supplied from the heatingdemander flows to the first boiler heat exchanger 32 through theinterior heat exchanger 22, but a compressed refrigerant does not flowto the interior heat exchanger 22, so heat heating water is notspecifically heated.

The heat pump boiler may be operated in a heat pump heating mode thatheats heating water only through the interior heat exchanger 22, and aboiler heating mode that heats heating water only through the firstboiler heat exchanger 32 without driving the compressor 10.

FIG. 5 is a block diagram of a controller and relevant components of anexample heat pump boiler. Hereafter, a controller and relevantcomponents are described with reference to FIG. 5 .

The heat pump boiler includes a controller 40 that controls driving ofthe compressor 10 or combustion in the combustor, and adjusts thedefrosting valve 24 in accordance with the operation modes.

The controller 40 can adjust the defrosting valve 24 in accordance withthe operation modes of the heat pump boiler. Further, the controller cancontrol the channel change valves 14 a, 14 b, and 14 c in accordancewith the operation modes of the heat pump boiler.

Referring to FIGS. 2A and 3 , the controller 40 controls the firstchannel change valve 14 a to connect the compressor 10 and thedefrosting valve 24, the second channel change valve 14 b to connect theexterior heat exchanger 12 and the compressor 10, the third channelchange valve 14 c to connect the interior heat exchanger 22 and theexterior heat exchanger 12, and the defrosting valve 24 to connect thecompressor 10 and the interior heat exchanger 22 in the hybrid heatingmode of the heat pump boiler.

Referring to FIGS. 2 b and 4, the controller 40 controls the firstchannel change valve 14 a to connect the compressor 10 and the exteriorheat exchanger 12, the second channel change valve 14 b to connect theexterior heat exchanger 12 and the defrosting valve 24, the thirdchannel change valve 14 c to connect the second boiler heat exchanger 34and the compressor 10, and the defrosting valve 24 to connect thecompressor 12 and the second boiler heat exchanger 34 in thedefrosting-heating mode of the heat pump boiler.

The heat pump boiler may further include an exterior temperature sensor42 that finds out exterior temperature. The controller 40 can adjust thechannel change valves 14 a, 14 b, and 14 c and the defrosting valve 24in accordance with exterior temperature found out by the exteriortemperature sensor 42.

FIG. 6 is a schematic of an example heat pump boiler.

Hereafter, a heat pump boiler is described mainly on the basis of thedifference from the heat pump boiler found out from FIGS. 1 to 4 withreference to FIG. 6 .

A heat pump boiler includes: a first boiler heat exchanger 32 that heatsa heating water using combustion heat; a combustor that providescombustion heat to the first boiler heat exchanger 32 by burning fuel; aexhauster 36 to which gas burned in the combustor is discharged; and asecond boiler heat exchanger 34 that is disposed in the exhauster 36 andallows heat exchange between a refrigerant and an exhaust gas.

The exhauster 36 extends from the first boiler heat exchanger 32 andguides the exhaust gas discharged through the first boiler heatexchanger 32. The second boiler heat exchanger 34′ may be disposed inthe exhauster 36 to which an exhaust gas is discharged.

According to a heat pump boiler of the present disclosure, one or moreeffects can be achieved as follows.

First, the technology described above can continuously perform heatingwithout stopping due to a defrosting operation in a heating operation,so there is also an advantage that it is possible to make a user feelpleasant.

Second, the technology described above can perform defrostingsimultaneously with heating, using the heat of an exhaust gas from aboiler, so there is also an advantage that the cost required for using aseparate heat source.

What is claimed is:
 1. A heat pump boiler comprising: a compressor thatis configured to compress refrigerant; an exterior heat exchanger thatis configured to transfer heat between refrigerant and exterior air; aninterior heat exchanger that is configured to transfer heat betweenrefrigerant and water; a channel change valve that is configured toprovide refrigerant compressed by the compressor to the exterior heatexchanger or the interior heat exchanger; a first boiler heat exchangerthat is configured to heat water that has passed through the interiorheat exchanger from heat generated through combustion; a second boilerheat exchanger that is configured to transfer heat between refrigerantand gas discharged from the first boiler heat exchanger; a defrostingvalve that is configured to provide refrigerant to the interior heatexchanger or the second boiler heat exchanger; an outdoor unit thatincludes the compressor, the exterior heat exchanger, and the channelchange valve; an indoor unit that includes the interior heat exchanger,the first boiler heat exchanger, and the second boiler heat exchanger; afirst refrigerant pipe that defines a channel for refrigerant dischargedfrom the outdoor unit and provided to the indoor unit; and a secondrefrigerant pipe that defines a channel for a refrigerant dischargedfrom the indoor unit and provided to the outdoor unit, wherein thedefrost valve provides refrigerant provided from the outdoor unitthrough the first refrigerant pipe to the interior heat exchanger or thesecond boiler heat exchanger.
 2. The heat pump boiler of claim 1,wherein based on the exterior heat exchanger operating as a condenser,the defrosting valve provides refrigerant discharged from the exteriorheat exchanger to the second boiler heat exchanger.
 3. The heat pumpboiler of claim 1, wherein based on the exterior heat exchangeroperating as an evaporator, the defrosting valve provides refrigerantdischarged from the compressor to the interior heat exchanger.
 4. Theheat pump boiler of claim 1, wherein the channel change valve includes:a first channel change valve that is configured to provide refrigerantdischarged from the compressor to the interior heat exchanger or theexterior heat exchanger; a second channel change valve that isconfigured to provide refrigerant discharged from the exterior heatexchanger to the compressor or the second boiler heat exchanger; and athird channel change valve that is configured to provide refrigerantdischarged from the interior heat exchanger to the exterior heatexchanger or provide refrigerant discharged from the second boiler heatexchanger to the compressor.
 5. The heat pump boiler of claim 4, whereinthe defrosting valve is configured to provide, to the interior heatexchanger, refrigerant that is provided through the first channel changevalve.
 6. The heat pump boiler of claim 4, wherein the defrosting valveis configured to provide, to the second boiler heat exchanger,refrigerant that is provided through the second channel change valve. 7.The heat pump boiler of claim 1, wherein: the first boiler heatexchanger includes: a sensible heat exchanger that heats water usingheat generated through combustion; and a latent heat exchanger thatheats water by absorbing condensation latent heat of an exhaust gas thathas passed through the sensible heat exchanger, and the second boilerheat exchanger is located downstream further than the latent heatexchanger in a traveling direction of gas that is burned in the firstboiler heat exchanger.
 8. The heat pump boiler of claim 1, comprising:an exhauster that extends from the first boiler heat exchanger and thatis configured to guide exhaust gas discharged by the first boiler heatexchanger, wherein the second boiler heat exchanger is located in theexhauster.